'\"macro stdmacro
.\"
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.\"
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.TH PMDISCOVERSETUP 3 "PCP" "Performance Co-Pilot"
.SH NAME
\f3pmDiscoverSetup\f1,
\f3pmDiscoverSetSlots\f1,
\f3pmDiscoverSetEventLoop\f1,
\f3pmDiscoverSetConfiguration\f1,
\f3pmDiscoverSetMetricRegistry\f1,
\f3pmDiscoverClose\f1 \- asynchronous archive location and contents discovery services
.SH "C SYNOPSIS"
.ft 3
#include <pcp/pmwebapi.h>
.sp
.ad l
.hy 0
.in +8n
.ti -8n
int pmDiscoverSetup(pmDiscoverModule *\fImodule\fP, pmDiscoverCallBacks *\fIcallbacks\fP, void *\fIarg\fP);
.sp
.ti -8n
int pmDiscoverSetSlots(pmDiscoverModule *\fImodule\fP, void *\fIslots\fP);
.br
.ti -8n
int pmDiscoverSetEventLoop(pmDiscoverModule *\fImodule\fP, void *\fIuvloop\fP);
.br
.ti -8n
int pmDiscoverSetConfiguration(pmDiscoverModule *\fImodule\fP, struct dict *\fIconfig\fP);
.br
.ti -8n
int pmDiscoverSetMetricRegistry(pmDiscoverModule *\fImodule\fP, struct mmv_registry *\fIregistry\fP);
.sp
.ti -8n
int pmDiscoverClose(pmDiscoverModule *\fImodule\fP);
.sp
.in
.hy
.ad
cc ... \-lpcp_web
.ft 1
.SH DESCRIPTION
The
.B pmDiscoverSetup
and related functions are an integral part of the
.B libpcp_web
API library, as used by and described in
.BR pmwebapi (3),
.BR pmproxy (1),
.BR pmseries (1)
and elsewhere.
These functions provide an asynchronous event driven mechanism to automatically
discover PCP archives created by
.BR pmlogger (1)
and any other application capable of writing PCP archives.
This includes
.BR pmrep (1)
and other applications using the
.BR LOGIMPORT (3)
API for importing performance data into the PCP infrastructure and writing PCP archives.
.P
The
.B pmDiscover
API services dynamically discover, monitor and manage directories of PCP archives as they
are created, written to, compressed and eventually deleted.
The underlying archive life-cycle is normally managed by the PCP log management infrustructure (see
.BR pmlogger_daily (1)).
Discovered archives that are active (currently being written) are "log-tailed" to extract near live/real-time
performance data which is then passed off via registered callbacks for further processing.
Archives that are compressed or inactive are tracked/monitored but not log-tailed.
.P
The
.B pmDiscover
routines can be configured to automatically discover and monitor PCP archives in one or more
directories as specified in the
.BR pmDiscoverModule ,
which is initially set up by calling
.B pmDiscoverSetConfiguration
to create a
.I module
of type
.BR pmDiscoverModule ,
as described above.
The resulting
.I module
is then passed to
.BR pmDiscoverSetup
along with an initialized structure of
.I callbacks
of type
.BR pmDiscoverCallBacks .
.P
Setting up a discovery module and callbacks would normally declare an instance of
.BR pmDiscoverSettings ,
e.g.
.sp
.nf
.in +0.5i
#include <pcp/pmwebapi.h>

static pmDiscoverSettings someapp_discover = {
    .callbacks.on_source        = pmSomeappDiscoverSource,
    .callbacks.on_closed        = pmSomeappDiscoverClosed,
    .callbacks.on_labels        = pmSomeappDiscoverLabels,
    .callbacks.on_metric        = pmSomeappDiscoverMetric,
    .callbacks.on_values        = pmSomeappDiscoverValues,
    .callbacks.on_indom         = pmSomeappDiscoverInDom,
    .callbacks.on_text          = pmSomeappDiscoverText,
    .module.on_info             = someapp_logging_function,
};
.in
.fi
.P
And then initialize this with API calls similar to the following:
.sp
.nf
.in +0.5i
pmDiscoverSetEventLoop(&someapp_discover.module, myevents);
pmDiscoverSetConfiguration(&someapp_discover.module, myconfig);
pmDiscoverSetMetricRegistry(&someapp_discover.module, metric_registry);
pmDiscoverSetup(&someapp_discover.module, &someapp_discover.callbacks, &privatedata);
.in
.fi
.P
The above code must then implement each of the declared callbacks
etc. to do whatever is required with the data passed in to the callback.
Prototypes for these callbacks can be found in the
.B pmwebapi.h
header.
The callbacks will be made asynchronously, as archives are discovered or deleted
and as new data is written to active archive log volume and metadata files.
.P
In the case of
.BR pmproxy (1),
callbacks are registered to capture performance data, which is then sent to
.BR redis (1)
as the database back-end for fast scalable time-series queries by clients
of the
.BR PMWEBAPI (3)
REST API services.
Such clients include the
.BR pmseries (1)
application and
.BR pmproxy (1),
which is the back-end REST API server for
.BR grafana-pcp ,
a native
.BR grafana-server (1)
data-source for PCP.
.SH FILES
The default archive directory is
.BR $PCP_LOG_DIR ,
which is normally
.BR /var/log/pcp/pmlogger .
The API recursively descends all sub-directories and also dynamically discovers any new directories or archives found therein.
.SH DIAGNOSTICS
Generally zero on success, or on error a negative return code, see
.BR pmerr (1).
.SH SEE ALSO
.BR grafana-server (1),
.BR pmerr (1),
.BR pmlogger (1),
.BR pmproxy (1),
.BR pmseries (1),
.BR PMWEBAPI (3),
.BR mmv_stats_registry (3),
.BR PMAPI (3),
.BR pmErrStr (3),
.BR pcp.conf (5)
and
.BR pcp.env (5).
